Actuate supplemental restraint system, function - GF91.60-P-2012CAM
MODEL 207.3/4
Function requirements, general
- Circuit 15R ON
The status of circuit 15R is sent by the electronic ignition lock control unit (N73) via chassis CAN (CAN E) (up to 31.5.13) or via chassis CAN 1 (CAN E1) (as of 1.6.13) to the supplemental restraint system control unit (N2/10).
Actuate Supplemental Restraint System, general
The supplemental restraint system continuously monitors the occupancy of the front passenger seat and the status of the front seat belts (fastened or not fastened) and adapts its triggering behavior on the basis of this information.
The Trigger Supplemental Restraint System function includes the following subfunctions:
- Function sequence system monitoring
- Function sequence for evaluation of occupancy status of front passenger seat
- Function sequence for detecting status of front seat belts
- Function sequence for impact detection
- Function sequence for frontal impact
- Function sequence for side impact
- Function sequence for rear end collision
- Function sequence for rollover
- Function sequence for additional functions in the event of a crash
Function sequence system monitoring
The supplemental restraint system control unit constantly monitors the supplemental restraint system and reports faults via the supplemental restraint system indicator lamp (A1e15) and the multifunction display (A1p13) in the instrument cluster (A1) to the driver. The request for output of the corresponding messages is sent by the supplemental restraint system control unit on vehicles up to 31.5.13 via chassis CAN to the instrument cluster. On vehicles as of 1.6.13, the supplemental restraint system control unit sends the request via chassis CAN 1, front SAM control unit with fuse and relay module (N10/1) and chassis CAN 2 (CAN E2) to the instrument cluster.
In addition, the automatic child seat recognition warning lamp (S6/1e1) in the instrument panel switch group (S6/1) (up to 31.5.13) or the automatic child seat recognition warning lamp (N72/1e1) (as of 1.6.13) in the upper control panel control unit (N72/1) is switched on. The request to switch on the automatic child seat recognition warning lamp is sent by the supplemental restraint system control unit via chassis CAN (up to 31.5.13) or via chassis CAN 1 (as of 1.6.13) to the front SAM control unit, which actuates the automatic child seat recognition warning lamp accordingly via instrument panel LIN (LIN 1). Any faults are stored in the nonvolatile memory of the Supplemental Restraint System control unit. The Supplemental Restraint System indicator lamp and the automatic child seat recognition warning lamp are switched off following a successful self-test after t = 4 s.
Function sequence for evaluation of occupancy status of front passenger seat
The triggering behavior of the restraint equipment at the passenger side is adapted on the basis of the occupancy status of the front passenger seat.
Without code (U18) Automatic child seat recognition (ACSR [AKSE]) and without code (U10) Front passenger seat with weight sensing, the status of the seat occupied recognition does not have any influence on the triggering behavior of the supplemental restraint system.
Detailed information about the seat occupied recognition can be found in the separate partial function "Passenger-side seat occupied recognition, function".
Function sequence for detecting status of front seat belts
The triggering behavior of the restraint equipment is adapted on the basis of the status of the seat belts (fastened or not fastened). The driver seat belt buckle restraint system switch (S68/3) or the front passenger seat belt buckle restraint system switch (S68/4) is actuated by the belt latch which is inserted into the belt buckle. The status of the belt buckle restraint system switch is directly read in by the supplemental restraint system control unit.
The status of the rear seat belts does not have any influence on the deployment behavior of the supplemental restraint system.
Function sequence for impact detection
The supplemental restraint system control unit determines the acceleration forces acting on the vehicle with the aid of the following sensors:
- Integrated sensors
- Left sidebag sensor (A53)
- Right sidebag sensor (A54)
- Left frontal acceleration sensor (B48/1)
- Right frontal acceleration sensor (B48/2)
- Left front door pressure sensor (B48/7)
- Right front door pressure sensor (B48/8)
The signals of the sensors are read in directly by the Supplemental Restraint System control unit.
A distinction can be made between the following types of impact by evaluating the signals of these sensors:
- Head-on collision
- Side-on collision
- Rear end collision
- Roll-over
Function sequence for frontal impact
The supplemental restraint system control unit detects a frontal impact by evaluating the signals from the following sensors:
- Integrated sensors
- Left frontal acceleration sensor
- Right frontal acceleration sensor
The deployment of the restraint equipment takes place depending on the severity of the impact, the occupancy of the front passenger seat and the status of the seat belts.
The following squibs can be ignited (at most):
- Driver emergency tensioning retractor squib (R12/1)
- Passenger emergency tensioning retractor squib (R12/2)
- Front passenger airbag squib 1 (R12/4)
- Front passenger airbag squib 2 (R12/5)
- Left rear emergency tensioning retractor squib (R12/6)
- Right rear emergency tensioning retractor squib (R12/7)
- Driver airbag squib 1 (R12/13)
- Driver airbag squib 2 (R12/14)
- Driver kneebag squib (R12/25)
The squibs are actuated directly by the Supplemental Restraint System control unit.
The following situations are taken into account:
- Occupancy status of the front passenger seat:
The supplemental restraint system control unit uses the current occupancy to determine whether the front passenger airbag unit should be triggered at all or in 1 or 2 stages.
- Driver belt buckle status:
If the driver seat belt buckle restraint system switch detects that a belt latch is not inserted into the belt buckle, the driver airbag unit with advanced ignition timing is triggered instead of the driver emergency tensioning retractor unit.
- Front passenger belt buckle status:
If the front passenger belt buckle restraint system switch detects that a belt latch is not inserted into the belt buckle with an occupied front passenger seat, the front passenger airbag unit with advanced firing point is triggered instead of the front passenger emergency tensioning retractor unit.
Function sequence for side impact
The supplemental restraint system control unit detects a side impact by evaluating the signals from the following sensors:
- Integrated sensors
- Left sidebag sensor
- Right sidebag sensor
- Left front door pressure sensor
- Right front door pressure sensor
The restraint equipment is deployed depending on the severity of the impact and occupancy of the front passenger seat.
The following squibs can be ignited (at most):
- Driver ETR [GUS] squib
- Front passenger ETR [GUS] squib
- Left rear emergency tensioning retractor squib
- Right rear emergency tensioning retractor squib
- Driver sidebag squib (R12/9) (model 207.3)
- Front passenger sidebag squib (R12/10) (model 207.3)
- Left rear sidebag squib (R12/11) (with code (293) Left and right rear sidebag)
- Right rear sidebag squib (R12/12) (with code (293) Left and right rear sidebag)
- Left windowbag squib (R12/22) (model 207.3)
- Right windowbag squib (R12/23) (model 207.3)
- Left head/thoraxbag squib (R12/39) (model 207.4)
- Right head/thoraxbag squib (R12/40) (model 207.4)
- Driver pelvis airbag squib (R12/41) (with code (291) PELVIS AIRBAG (PELVISBAG))
- Front passenger pelvis airbag squib (R12/42) (with code (291) PELVIS AIRBAG (PELVISBAG))
The squibs are actuated directly by the Supplemental Restraint System control unit.
The following state is taken into consideration:
The Supplemental Restraint System control unit makes a decision about triggering the front passenger sidebag unit based on the current occupancy of the front passenger seat.
Function sequence for rear end collision
The supplemental restraint system control unit detects a rear-end collision by evaluating the signals from the following sensors:
- Integrated sensors
- Left sidebag sensor
- Right sidebag sensor
- Left frontal acceleration sensor
- Right frontal acceleration sensor
The deployment of the restraint equipment takes place depending on the severity of the impact and the status of the seat belts.
The following squibs can be ignited (at most):
- Driver ETR [GUS] squib
- Front passenger ETR [GUS] squib
- Left rear emergency tensioning retractor squib
- Right rear emergency tensioning retractor squib
The squibs are actuated directly by the Supplemental Restraint System control unit.
In addition, the following components are actuated by the Supplemental Restraint System control unit:
- Driver seat NECK-PRO head restraint solenoid (Y24/12)
- Front passenger seat NECK-PRO head restraint solenoid (Y24/13)
Triggering of the NECK-PRO head restraints is also described in the separate function description "Driving assistance systems, function" in the "Rear-end PRE-SAFE, function" subfunction.
The following situations are taken into account:
- Driver belt buckle status:
If the driver belt buckle restraint system switch detects that a belt latch has not been inserted into the belt buckle, the driver emergency tensioning retractor unit is not deployed.
- Front passenger belt buckle status:
If the front passenger belt buckle restraint system switch detects that a belt latch has not been inserted into the belt buckle, the front passenger emergency tensioning retractor unit is not deployed.
Function sequence for rollover
The supplemental restraint system control unit detects a rollover by evaluating the signals from the integrated sensors: Only one roll-over around the longitudinal vehicle axis can be detected.
The following squibs can be ignited (at most):
- Driver ETR [GUS] squib
- Front passenger ETR [GUS] squib
- Left rear emergency tensioning retractor squib
- Right rear emergency tensioning retractor squib
The squibs are actuated directly by the Supplemental Restraint System control unit.
The following situations are taken into account:
- Driver belt buckle status:
If the driver belt buckle restraint system switch detects that a belt latch has not been inserted into the belt buckle, the driver emergency tensioning retractor unit is not deployed.
- Front passenger belt buckle status:
If the front passenger belt buckle restraint system switch detects that a belt latch has not been inserted into the belt buckle, the front passenger emergency tensioning retractor unit is not deployed.
On model 207.4, the roll bars are triggered in the event of a rollover. The supplemental restraint system control unit actuates the left roll bar airbag squib (R12/45) and the right roll bar airbag squib (R12/46). Within split seconds, the rear head restraints in which the roll bars are integrated are extended.
Function sequence for additional functions in the event of a crash
The additional functions in the event of a crash include the following subfunctions:
- Function sequence for activating the hazard warning function
- Function sequence for switching on the interior illumination
- Function sequence for opening the central locking (CL [ZV])
- Function sequence for opening the side windows
- Function sequence for shutting off the engine
- Function sequence for triggering the pyrofuse
- Function sequence for switching off the air conditioning system (as of 1.6.13)
- Function sequence for shutting off the stationary heater (STH) (with code (228) Stationary heater)
- Function sequence for automatic emergency call (with code (359) TELEAID emergency call system (up to 31.5.13) or code (348) Emergency call/assist system)
- Function sequence for activating crash-active exit aid (with code (275) Memory package (Driver seat, steering column, mirrors))
Function sequence for activating the hazard warning function
The hazard warning flasher function is activated automatically in order to warn other road users in the event of an accident. The supplemental restraint system control unit sends the crash signal via chassis CAN (up to 31.5.13) or via chassis CAN 1 (as of 1.6.13) to the front SAM control unit. The front SAM control unit initiates the hazard warning flasher function by issuing the flasher frequency via interior CAN.
Detailed information about the hazard warning flasher function can be found in the separate function description "Exterior lights, function" in subfunction "Turn signal light actuation, function".
Function sequence for switching on the interior illumination
In order to make it easier for the vehicle occupants or persons giving assistance to find their way around inside the vehicle in the event of an accident when it is dark, the interior illumination is automatically switched on. The supplemental restraint system control unit sends the crash signal via chassis CAN (up to 31.5.13) or via chassis CAN 1 (as of 1.6.13) to the front SAM control unit. The front SAM control unit then activates the interior illumination.
Detailed information about the interior illumination can be found in the separate function description "Interior illumination function".
Function sequence for opening the central locking (CL [ZV])
In order to make it possible for helpers gain access to vehicle occupants who may be injured in the event of an accident, the central locking is automatically unlocked. The supplemental restraint system control unit sends the crash signal via chassis CAN (up to 31.5.13) or via chassis CAN 1 (as of 1.6.13), front SAM control unit and interior CAN to the left front door control unit (N69/1) and the right front door control unit (N69/2).
The central locking is unlocked after a waiting time of t = 8 to 11 s.
Detailed information about the CL [ZV] can be found in the "Central locking (CL [ZV]), function" subfunction of the separate function description "Theft protection and locking function description".
Function sequence for opening the side windows
Smoke particles are produced in the vehicle interior when the pyrotechnical restraint equipment is triggered. The side windows are opened automatically leaving a gap in order to allow these smoke particles to quickly disperse. The supplemental restraint system control unit sends the crash signal via chassis CAN (up to 31.5.13) or via chassis CAN 1 (as of 1.6.13), front SAM control unit and interior CAN to the left front door control unit, the right front door control unit and the rear control unit (N22/6).
Detailed information on opening the side windows can be found in the separate function description "Windows and sightproofing function description" in the "Power windows (EFH), function" subfunction.
Function sequence for shutting off the engine
After an accident, the engine is automatically turned off to reduce the risk of fire. The supplemental restraint system control unit sends the crash signal via chassis CAN (up to 31.5.13) or via chassis CAN 1 (as of 1.6.13) to the CDI control unit (N3/9) (with diesel engine) or to the ME-SFI [ME] control unit (N3/10) (with gasoline engine). This then causes the engine to be shut off.
The supplemental restraint system control unit is also connected over a direct line to the CDI control unit or the ME-SFI [ME] control unit. A request is also sent over this line to switch off the engine.
Function sequence for triggering the pyrofuse
In order to avoid the risk of fire after an accident, the pyrofuse 150 (F32f150) (without code (B03) ECO start/stop function) or the pyrofuse (F63) with code (B03) ECO start/stop function) is deployed.
Inside the pyrofuse housing, the main line is designed as busbar with predetermined fracture point (3). After a crash event has occurred, the pyrofuse is directly actuated by the supplemental restraint system control unit. When the pyrofuse is actuated, pressure builds up in the chamber (1). The piston (2) then moves against the predetermined fracture point disconnecting the bus bar.
Time sequence:
Piston movement starts after t = 300 μs.
Busbar disconnection is complete after t = 450 μs.
By triggering the respective pyrofuse, the starter (M1) and the alternator (G2) are quickly and reliably disconnected from the on-board electrical system.
Function sequence for switching off the air conditioning system (as of 1.6.13)
In order to prevent hazardous gases from entering the vehicle interior after an accident, the automatic climate control control and operating unit (N22/7) shuts off the air conditioning and closes the air recirculation flap. The supplemental restraint system control unit transmits the crash signal via the chassis CAN 1, the front SAM control unit and the interior CAN to the automatic air conditioning control and operating unit.
Detailed information about switching off the air conditioning can be found in the separate function description "Automatic climate control, function" in the "Automatic climate control regulation, function" subfunction.
Function sequence for switching off the STH (with code (228) Stationary heater)
After an accident, the stationary heater is automatically turned off to reduce the risk of fire. The supplemental restraint system control unit sends the crash signal via chassis CAN (up to 31.5.13) or via chassis CAN 1 (as of 1.6.13), front SAM control unit and interior CAN to the stationary heater control unit (A6n1), which prompts a shutoff of the stationary heater.
Detailed information about the stationary heater can be found in the separate function description "Stationary heater (STH), function".
Function sequence for automatic emergency call (with code (359) TELEAID emergency call system (up to 31.5.13) or code (348) Emergency call/assist system)
An emergency call is made automatically after an accident. The supplemental restraint system control unit sends the crash signal via chassis CAN (up to 31.5.13) or via chassis CAN 1 (as of 1.6.13), front SAM control unit and diagnostic CAN (CAN D) to the emergency call system control unit (N123/4), which makes the automatic emergency call.
The crash signal is also sent over a direct line from the Supplemental Restraint System control unit to the emergency call system control unit.
Detailed information on the automatic emergency call can be found in the separate function description "Function description for telematics" in the subfunction "Emergency call system, function".
Function sequence for activating crash-active exit aid (with code (275) Memory package (Driver seat, steering column, mirrors))
In order to make it easier for the driver to get out of the vehicle and for first aiders to recover the driver from the vehicle after an accident, the steering column is automatically moved upwards in the event of the following actions:
- Driver door opened
- Change of status from circuit 15C ON to circuit 15C OFF
The supplemental restraint system control unit sends the crash signal via chassis CAN (up to 31.5.13) or via chassis CAN 1 (as of 1.6.13), front SAM control unit and interior CAN to the driver seat control unit (N32/1). The driver seat control unit initiates upward adjustment of the steering column.
Detailed information about the crash-active easy exit feature can be found in the separate "Electrical seats, function" function description in the "Electrically adjustable steering column (ESC [EVL]), function" subfunction.
| Actuate Supplemental Restraint System, electrical function schematic | MODEL 207.3/4 up to model year 2014 | PE91.60-P-2055-97EAA | |
| MODEL 207.3/4 as of model year 2014 | PE91.60-P-2055-97EAB | ||
| Overview of system components for supplemental restraint system | GF91.60-P-9996CAM |